January 19th Winter Storm: Final Call

We're a little more than 12 hours from the onset of one of the biggest winter storms to hit Central Ohio in a couple seasons and we're no closer to officially nailing down a solid forecast for where and how much snow will fall. This is going to be a storm where we have to watch and micromanage changes throughout the day tomorrow.

This morning the NWS issued Winter Storm Warnings along and north of I-70, and then by afternoon extended them another row of counties south and west:

This will be a major snow maker first and foremost. Those warnings in northern Ohio are there specifically because of these high snowfall chances. The further south you go, yeah, it'll snow some, but the real issue there will be the freeze over of wet roads after sunset when a brutally cold air mass wraps in on the backside.

As models have honed in on a solution for this storm, the threat of an ice storm has mostly diminished. It appears instead of cold air rushing in at the surface, leaving warm air aloft, most areas where it's 32° or colder will be just about freezing all the way through the column.

This is the part of the forecasting that becomes nearly impossible to pinpoint. Just north of the rain/snow line will be areas of extremely heavy snowfall. This is where heavy moisture is getting pushed from the rain side to the snow side, and all that water has to go somewhere. It'll form ice crystals and go straight to the surface as huge wet flakes.

So without further delay, here's what I'm thinking for tomorrow:

This isn't as simple as throwing together a snow map and calling it a day. This storm is almost going to be a two parter. Precip starts shortly after sunrise tomorrow as snow, a mix and rain in the areas shaded above. For a large portion of the day we'll see that rain/mix/snow line fluctuate north and south as different pieces of energy surge north from the parent low pressure. By late afternoon or early evening, areas along and north of I-70 may see a complete stop in precip. That's when cold air surges in and we get the backside of the storm swing up from the south, and all areas begin to change over to snow. This is probably where most areas will get the highest accumulation too.

The lines drawn above cannot be set in stone. This is just a best guess where boundaries will set up. As I said earlier, this will have to be micromanaged throughout the day to see exactly where everything sets up. Just because you start out as snow doesn't mean you'll stay like that all day, and vice versa.

I think there's a good chance that somewhere in Central Ohio sees a foot of snow out of this, I just couldn't tell you where. An axis of deformation will setup somewhere for several hours, and that small area will hit the snow jackpot.

Tomorrow I'm trying something new... instead of a LiveBlog, I'm going with LiveTweeting. Twitter has been a good platform to get off short thoughts without having to write a whole post, and that seems to play perfectly in to a storm like this. Be sure to click the link at the top of the page to follow me and join in the conversation tomorrow. It should be a fun one!